Method of controlling combustion

摘要

A method of controlling combustion in a furnace of a boiler or the like having a burner for a main combustion and a burner for a reducing combustion in order to effect combustion for furnace denitrification. The method comprises the steps of: estimating the NOx generation amount from data on a flame formed by the main combustion; estimating the reducing agent generation amount from data on a flame formed by the reducing combustion; and controlling the flow rates of fuel and air supplied for the main and reducing combustions so that the amount of NOx emission as the difference between the NOx generation amount and the reducing agent generation amount is below a specified value. In practice, each of the NOx generation amount and the reducing agent generation amount is estimated from the flame pattern, the flame volume, the distance between the outlet of the burner concerned and the root of the flame concerned, etc., thereby to distributively control the flow rates of fuel and air supplied to each of the main combustion burner and the reducing combustion burner so that the amount of NOx emission is below a specified value.